4.3 carbon cycling

Question 1

what are phototrophs!

Answer 1

plants! use light energy to convert co2 from envt into carbon compounds

Question 2

what are autotrophs!

Answer 2

organism making organic molecules using abiotic envt

Question 3

how do aquatic plants take up carbon

Answer 3

dissolved co2 / hydrogen carbonate in water diffuses into leaves

Question 4

co2s role in photosynthesis?

Answer 4

used in the calvin cycle to make carbohydrates and more complex carbon compounds

Question 5

co2 is (weight) and thus tends to rise/sink?

Answer 5

heavier than other gases

sink
= readily available to photosynthesisers

Question 6

solubility of CO2

Answer 6

quite low – 0.88-0.65cm3 of co2 / g of water (temps 20-30degC)

Question 7

how does solubility of co2 change with pressure

Answer 7

incr pressure = incr solubility of CO2

Question 8

how does co2 dissolve into water (solutbility and pressure r/s)

Answer 8

co2 heavy = sinks = incr pressure on water surface + waves = dissolve

Question 9

state the co2 concentration changes in the winter vs spring+summer

Answer 9

winter: co2 conc incr

spring/summer: co2 conc decr

Question 10

why does co2 concentration incr in the winter

Answer 10

• plants dormant, leaves lost
• more fuel – heat houses
• organisms still respiring

Question 11

why does co2 concentration decr in spring/summer

Answer 11

trees more leaves!

Question 12

methane is oxidised into….

Answer 12

co2 and water

Question 13

what is methane produced by

Answer 13

methanogenic archaeans (single-cell prokaryotes)

Question 14

what is methane produced from + conditions + what happens after

Answer 14

from organic matter

anaerobic conditions

released into atmos / accumulated underground

Question 15

what are Ruminants

Answer 15

mammals that have a MUTUALISTIC r/s with metahnogenic archaeans

help them digest cellulose from cell walls of plants they eat = creates methane

eg cow

Question 16

4 steps of methane production through ruminants

Answer 16

1. ruminants chew on plants = breaking down the molecules
2. organic matter first changed to organic acids and alcohol (Acidogenesis)
3. other bacteria convert org. acids and alcohol –> acetate + co2 + hydrogen
4. methanogenic bacteria prod methane thru: reaction of co2 + h2 OR breakdown of acetate

Question 17

2 ways that metahnogenic bacteria in ruminants can produce methane

Answer 17

1. reaction of co2 and h2
   CO2 + 4H2 –> CH4 + 2H2O
2. breakdown of acetate (methanogenesis)
   CH3COO- + H+ –> CH4 + CO2

Question 18

define hydrolysis

Answer 18

chemical process of breaking large polymers into dimers/monomers using WATER

Question 19

define acidogenesis

Answer 19

chemical process by which bacteria convert organic matter –> organic acids + alcohol

Question 20

define acetogenesis

Answer 20

chemical process in which bacteria converts organic acids and alcohol into acetate

Question 21

define methanogenesis

Answer 21

chem process in which metahnogenic bacteria produces methane thru co2 + h2 OR breakdown of acetate

Question 22

arrange these in order: acidogenesis, methanogenesis, acetogenesis

Answer 22

1. acidogenesis – org matter –> org acids + alcohol
2. acetogenesis –> acetate
3. methanogenesis –> breakdown of acetate

Question 23

what is methane oxidised into

Answer 23

co2 and water

Question 24

when does peat form

Answer 24

when organic matter is NOT fully decomposed bc of acidic/anaerobic conditions in waterlogged soils

Question 25

how do waterlogged areas lead to peat formation 4

Answer 25

1. stagnant water = anaerobic envt
2. envt progressively acidified = saprotrophs die
3. remaining org matter only PARTIALLY digested
4. new materials compress the layer = peat

Question 26

what is peat?

Answer 26

partially digested dead organic matter
that forms in acidic, water-saturated soil

• contains large amts of carbon, can be compressed into coal after time

Question 27

uses of peat 4

Answer 27

• substitute for firewood
• incr moisture holding capacity of soil (horticulture)
• incr water infiltration rate
• acidify soils

Question 28

what are fossil fuels

Answer 28

organic material that has been compressed over time to form coal, oil, and fas

Question 29

what does coal form from!

Answer 29

peat

Question 30

how are oil and gas formed

Answer 30

similar to peat and coal! but at the bottom of lakes and oceans

Question 31

where can
1. coal
2. gas and oil
be found?

Answer 31

coal: thick layers beneath the surface hashtag minecraft

oil and gas: porous rock
eg gas reservoirs: deep in earth, high pressure conditions = gas in liquid form

Question 32

how does combustion release carbon!

Answer 32

as carbon dioxide

Question 33

what happens (rock-wise) when molluscs, coral, and crustaceans die?

Answer 33

high carbon content in shells and exoskeletons
= calcium carbonate becomes part of sedimentary rock (if conditions arent too acidic)

Question 34

what is a resevoir?

Answer 34

place where a certain element has accumulated / pooled

Question 35

when carbon moves from one resevoir to another its called a _____

Answer 35

flux

Question 36

draw a diagram of the carbon cycle

Answer 36

include interactions between
- co2 in atmos + hydrosphere
- carbon in fossil fuels
- carbon in dead organic matter
- carbon in consumers
- carbon in producers

Question 37

what unit is used when measuring carbon

Answer 37

gigatonnes (Gt): 10^15 g

Question 38

2 human acitivities adding to incr atmospheric co2 and methane

Answer 38

incr fossil fuel combustion

incr livestock farms

Question 39

why is estimating carbon fluxes important

Answer 39

predict impacts of climate change, reduce carbon emissions

• can calculate atmospheric carbon increases

Question 40

how is methane oxidised

Answer 40

reaction with hydroxyl radicals – highly reactive
= co2 + h2o